Improvement in compounds for hardening bar-iron



UNITED STATES PATENT OFFICE.

FRANKLIN E. BLAKE, OF MA'TTOON, ILLINOIS.

Specification forming part of Letters Patent No. 125,009, dated March 26, 1872.

' inyimprovement: Blue vitriol, oxalic acid, carbonate of ammonia, pure saltpeter, muriate of tin, (crystals,) equal parts.

Mode of Preparation.

Dissolve the chemicals in a (q. s.) suflicient quantity of ninety-six per cent. alcohol. After all is dissolved, put in pine sawdust, as much'as the solution will hold without dripping. Then pack the iron to be steelified with the compound in an iron case made perfectly air-tight by luting with fire-clay. Then put the case into a furnace and keep it at a cherry-red about thirty minutes, for steelifying the iron, after which let it cool gradually. This compound can be used a number of times and produce good results.

For case-hardening bar-iron, use the same material and process; and while red hot plunge the iron into the following compound, as follows: Three gallons of strong alkali; one pound saltpeter (nitrate of potassa); and muria-te of tin, one-quarter pound.

The sample of one-half-inch square ironth at accompanies this specification and drawing was broken before it was converted into steel, and shows the fibrous grain at the end; and

after going through the steelifying process it was broken off at the other end, and shows that the fibrous nature has been changed to crystal, and the whole piece converted into steel, that can be worked the same as any other steel.

The sample piece of iron one-half inch thick and one and one-quarter inch wide shows the case-hardening; and we claim that bar-iron case-hardened by this process can be heated and worked the same as steel, and has this advantage over all other case-hardening with which we are acquainted-of being tempered in water the same as English or bar-steel, without the trouble of re-case-hardening. This is a great advantage over other modes of casehardening, as other case-hardened work will spring and get out of shape. Again, iron casehardened by this process will not have any blisters, and will be strengthened considerable, thus making my invention of vast public utility.

Claim.

1 claim The compound herein described, with the privilege of varying the proportions of the ingredients named, so as always to produce the same results, substantially as or for the purpose herein set forth.

In testimony whereof I have signed myname to this specification in the presence of two subscribing witnesses.

FBAN KLIN E. BLAKE.

W'itn esses J. P. SoU'rHARD, E. O. FRINK. 

